The present invention generally relates to an apparatus, method and medium for providing an optical effect using a series of lenticules placed on a medium. In a more particular embodiment, the present invention relates to an apparatus, method and medium for providing an optical effect using a series of spherical-like lenticules printed on a medium using a printer.
Different technologies may be used to create two-dimensional media that provides xe2x80x9cspecialxe2x80x9d optical effects, such as the illusion of a three-dimensional presentation, or the illusion of an animated presentation. Parallax barrier displays, for instance, provide an opaque screen positioned over an image-bearing medium. The image-bearing medium includes a series of stripes of image information arranged in interleaved fashion. The screen includes a plurality of slits that serve as windows for viewing the stripes of information in the image presentation. In one configuration, a viewer may perceive different selections of stripes depending on his or her orientation with respect to the display. This effect allows the designer of the display to provide various types of animation effects. That is, a viewer may perceive that the display is xe2x80x9cchangingxe2x80x9d its image presentation as he or she walks by the display. In another configuration, a viewer""s left eye may perceive a different selection of stripes than the viewer""s right eye. This effect allows the designer to provide various stereoscopic effects.
Another technology for providing optical effects uses lenticular display sheets. As shown in FIG. 1, a typical lenticular arrangement 100 includes an array of narrow cylindrical lenses 102 (also referred to as xe2x80x9clenticulesxe2x80x9d) coupled to an image bearing-medium 104. Like the parallax barrier displays discussed above, the image-bearing medium 104 includes a series of stripes of image information arranged in interleaved fashion. In one configuration, the cylindrical lenticules on the lenticular sheet 102 focus the image information from the stripes in such a fashion that a viewer may perceive a first subset of strips (corresponding to a first scene) when positioned at a first orientation, and perceive a second subset of stripes (corresponding to a second scene) when positioned at a second orientation. This creates the illusion that the arrangement is xe2x80x9cchangingxe2x80x9d its image presentation as the viewer walks by the arrangement. In another configuration, a viewer""s left eye perceives a first subset of stripes (corresponding to a first scene), and a viewer""s right eye perceives another subset of stripes (corresponding to a second scene). This creates the illusion of depth.
FIGS. 2(a) and 2(b) explain the physical mechanism which enables lenticular arrangements to function in the above-described manner. More specifically, FIG. 2(a) shows how a lenticular arrangement achieves the illusion of changing scenes. In this exemplary embodiment, the image-bearing medium 202 (shown in cross section) presents three different scenes, namely scenes xe2x80x9cA,xe2x80x9d xe2x80x9cB,xe2x80x9d and xe2x80x9cC.xe2x80x9d These scenes are xe2x80x9cslicedxe2x80x9d into thin vertical stripes. The stripes are then interleaved so that a slice of scene xe2x80x9cAxe2x80x9d is positioned adjacent to a slice of image xe2x80x9cB,xe2x80x9d and a slice of scene xe2x80x9cBxe2x80x9d is positioned adjacent to a slice of image xe2x80x9cC.xe2x80x9d The thus formed image-bearing medium is coupled to the flat side of a lenticular sheet 204. In an alternative embodiment, it is known to print the image information directly on the flat side of the lenticular sheet 204.
In the case of FIG. 2(a), the lenticular sheet 204 focuses the light reflected from the image-bearing medium 202 so that a viewer perceives different scenes when positioned at different orientations with respective to the lenticular arrangement (or alternatively, the arrangement is tilted about axis xe2x80x9cxxe2x80x9d shown in FIG. 1, while the viewer remains stationary). Namely, the viewer may perceive the stripes corresponding to image xe2x80x9cCxe2x80x9d when stationed at position (1). The viewer may perceive the stripes corresponding to image xe2x80x9cBxe2x80x9d when stationed at position (2). And the viewer may perceive the stripes corresponding to image xe2x80x9cAxe2x80x9d when stationed at position (3).
Additional scenes may be included by interleaving additional stripes corresponding to respective additional scenes. The arrangement in FIG. 2(a) can accordingly create different effects depending on the content of the different scenes. The different scenes (e.g., xe2x80x9cA,xe2x80x9d xe2x80x9cB,xe2x80x9d and xe2x80x9cCxe2x80x9d) may represent different xe2x80x9csnap shotsxe2x80x9d in a motion sequence. Accordingly, the arrangement may create the illusion of motion as the user walks by the arrangement. Alternatively, the different scenes may have unrelated content.
FIG. 2(b) shows how a lenticular arrangement can achieve the illusion of a three dimensional presentation. Again, the image medium 262 (shown in cross section) presents three different scenes, namely scenes xe2x80x9cA,xe2x80x9d xe2x80x9cB,xe2x80x9d and xe2x80x9cC.xe2x80x9d These scenes are xe2x80x9cslicedxe2x80x9d in thin vertical stripes. The stripes are then interleaved so that a slice of scene xe2x80x9cAxe2x80x9d is positioned adjacent to a slice of image xe2x80x9cB,xe2x80x9d and a slice of scene xe2x80x9cBxe2x80x9d is positioned adjacent to a slice of image xe2x80x9cC.xe2x80x9d The thus formed image medium is coupled to the flat side of a lenticular sheet 264
In the case of FIG. 2(b), the lenticular sheet 264 focuses the light reflected from the image-bearing medium 262 so that, at a particular orientation, a viewer""s left eye perceives scene xe2x80x9cC,xe2x80x9d while the viewer""s right eye perceives scene xe2x80x9cB.xe2x80x9d The thus commingled image creates the perceived effect of a three dimensional presentation (when xe2x80x9cprocessedxe2x80x9d by the viewer""s brain).
The optical effects produced by the lenticular arrangement 100 shown in FIGS. 1 and 2 are observable when the viewer changes his or her orientation with respect to the normal of any lenticule. For instance, with reference to FIG. 1, a viewer will observe the optical effects when the viewer changes his or her position in the xe2x80x9chorizontalxe2x80x9d direction. This is equivalent to tilting the arrangement 100 about the axis xe2x80x9cx.xe2x80x9d However, a viewer will typically not observe the special optical effects when he or she changes position in the xe2x80x9cverticalxe2x80x9d direction of the arrangement (where the xe2x80x9cverticalxe2x80x9d direction corresponds to movement along the axes of the lenticules, such as axis xe2x80x9cxxe2x80x9d).
FIG. 3 shows another type of lenticular arrangement, referred to in the art as an xe2x80x9cintegramxe2x80x9d or xe2x80x9cintegral photograph.xe2x80x9d This arrangement replaces the sheet of cylindrical lenticules with a sheet 302 containing a regular array of spherical lenses on its surface 304. This sheet 302 is coupled to an image-bearing medium 306. This type of lens configuration has the potential of allowing a user to view optical effects when the viewer changes his position in both the xe2x80x9chorizontalxe2x80x9d and xe2x80x9cverticalxe2x80x9d directions relative to the surface of the arrangement. Exemplary patents disclosing the use of spherical lenses to create an optical effect include U.S. Pat. Nos. 3,683,773 and 5,933,276. Also note FIG. 6 and the accompanying discussion of Michael Halle, xe2x80x9cAutosteroscopic Displays and Computer Graphics,xe2x80x9d Computer Graphics, ACM SIGGRAPH, 31(2), May 1997, pp. 58-62.
There are shortcomings with respect to known lenticular-type arrangements. For instance, misalignment of the lenticular sheet with the underlying image-bearing medium may create visual artifacts in the perceived image. More specifically, alignment artifacts may result when the image-bearing medium is angularly skewed relative to the lenticular array. Alignment artifacts may also result when the spacing of the lenticules does not precisely match the spacing of the image stripes. Alignment artifacts may also result when the spacing between the lenticules or between the interlace stripes vary slightly from region to region. Generally speaking, alignment artifacts limit the resolution (granularity) in the resultant perceived image. Further, the additional care that must be taken to ensure proper alignment may increase the cost of production of these lenticular arrangements.
Some practitioners have attempted to remedy the alignment difficulties by, as noted above, printing the image directly on the flat side of a lenticular sheet. Others have proposed mechanisms for electronically detecting the alignment between the printed medium and the lenticular sheet using various types of sensor arrangements. However, these solutions may require complex and potentially expensive adaptations to existing printing mechanisms.
With respect to the use of integrams, the above-referenced Halle article states that integrams are less common than their cylindrical lenses counterparts mostly because their spatial resolution is scarified to directional information. Further, insofar as an integram sheet is coupled with an image-bearing medium in the manner described above, this technology suffers from all of the alignment difficulties described above. Indeed, these alignment problems may be exacerbated because of the need to align the sheet in both the horizontal and vertical directions relative to the image-bearing medium. These difficulties may have prevented those skilled in the art from appreciating the full potential of spherical lenses.
Additional unspecified deficiencies may exist in known lenticular displays.
There is accordingly a need for a more effective apparatus, method and medium for providing optical effects from a two-dimensional image-bearing medium.
The present invention addresses the above-identified needs, as well as additional unspecified needs.
One exemplary aspect of the invention pertains to an apparatus for producing an image-bearing medium that provides an optical effect. The apparatus includes a processor for controlling the operation of the apparatus, and an interface for receiving image information including multiple image elements. The apparatus further includes a printing head (such as an ink jet printing head) including a first dispensing mechanism for dispensing a colored ink, and a second dispensing mechanism for dispensing a clear ink. The processor includes printing logic for instructing the printing head to print at least one image element on a base medium using the first dispensing mechanism, and for printing at least one lens-like lenticule on the medium, at a prescribed position relative to the at least one image element, using the second dispensing mechanism. The at least one lenticule modifies a viewer""s perception of the at least one image element, to thereby achieve the optical effect. According to one embodiment, the clear ink forms a substantially spherical lenticule.
Another aspect of the invention pertains to a method for providing an optical effect. The method includes an initial step of accessing an image source containing image information including multiple image elements. The method then includes the steps of printing at least one image element on a base medium using a colored ink, and printing at least one lenticule on the base medium, at a prescribed position relative to the at least one image element, using a clear ink.
Another aspect of the invention pertains to an image-bearing medium for providing an optical effect. The image-bearing medium includes a base medium. The image-bearing medium further includes at least one image element printed directly on the base medium using a colored ink, and at least one lenticule printed directly on the base medium using a clear ink, at a prescribed position relative to the at least one image element.
The use of a printer to print lenticules directly on a base material (such as paper or a plastic transparency) reduces the alignment problems found in known lenticular arrangements. Further, the technique allows the formation of spherical lenticules with improved accuracy and ease compared to known systems, thus potentially eliminating some of the concerns that have been identified with respect to integral technology. This enables the development of new optical effects using the spherical lenses that have heretofore not been envisioned.